Temperature control in a tarantula vivarium is very important but not overly critical. Tarantulas are pretty tolerant of room temperature. So if you live in a house that's between around 72 degrees during the day, maybe drops a little bit, you're not going to need much more to keep your tarantula happy. If it gets below that degrees, I would start to put some supplemental heat on the cage.
Those come in many forms. The traditional one is a big, gaudy light on top with a light bulb of various types, various wattages, that depending on the type of tarantula you have. You may have to make it hot or humid. But we tend to just leave a very low wattage light on top so we can see the tarantula. And if we need heat, we put a heat pad. Traditionally, these go underneath the tank and warm the belly of a snake or a lizard. They're reptile products. But for a tarantula, we usually put them on the side or on the back.
They peel, and they stick. Some can be removed. Others are permanent. This gives the tarantula a side of the terrarium to go to. It's essential that this cord is then plugged into a rheostat, a temperature control device, and you set it and forget it. If it's below 68 degrees, the temperature controller will kick on, and that heat mat will get warm. If it hits the ambient temperature you desire, it shuts it all down and this becomes cold again. So the thing you don't want to do really is make it too hot that the tarantula has no place to go. A really hot tarantula terrarium usually is fatal for the animal. A little bit of cold it can tolerate. Most houses are not going to get that low in the degree part. So you don't have to worry about getting to cold. Too hot is what I'd be concerned about. And too hot, particularly with a lamp like this, which I certainly wouldn't put on a small tank.
This is a device that's used for a very, very large tank. The problem with a tarantula, of course, is dehydrating. Dehydration is one of the biggest problems with a tarantula if it's not kept correctly, if you don't give it the proper humidity and the hide spots. And people make the mistake of watering them incorrectly. So here's a great device that has come on the market. it's a simple little water bowl, but they've cleverly put a sponge. For years and years, we've been cutting up sponges from mom's kitchen, clean ones, and putting them in a water bowl, because tarantulas do not drink from a deep water bowl.
They're organs to breathe are underneath their body, and if they laid in an inch of water, they certainly would drown. So you want to just let them go into a bowl like this, and they suck the water off the top of it. Just keep this damp, and they suck the water down into their system and stay hydrated. So that's the way you water a tarantula. That's the way you keep it warm. It's a bit of a dicey situation to keep it warm enough the tarantula's happy, not too warm that it's going to be dehydrating. That's your job as the keeper. The life of the tarantula is in your hands. So do your homework, and everything will be fine.